Field of the Disclosure
The present disclosure relates to the field of power electronics, and more particularly, to a resonance-type contactless power supply, an integrated circuit and a constant voltage control method.
Description of the Related Art
Contactless power supply is widely used in electronic products, especially in low-power electronic products such as cellular phones, MP3 players, digital cameras, laptop computers, and the like, due to their convenience and availability. A conventional resonance-type contactless power supply typically has a resonance and magnetic coupling circuit, including a transmitting coil L1 and a receiving coil L2. The transmitting coil L1 and other components in a power transmitter constitute a transmitter-side resonant circuit. The receiving coil L2 and other components in a power receiver constitute a receiver-side resonant circuit. Electric energy is transferred in a contactless manner when the transmitter-side resonant circuit and the receiver-side resonant circuit have the same resonance frequency. The receiver-side resonant circuit is coupled to the transmitter-side resonant circuit by electromagnetic field, and thus resonates when the transmitter-side resonant circuit resonates. Typically, the above resonance frequency is referred to as a self-inductance resonance frequency.
When operating in the self-inductance resonance frequency, the conventional resonance-type contactless power supply functions as a current source and provides a relatively constant current to a load. Thus, the resonance-type contactless power supply cannot be used for a load which needs a constant voltage.